The present invention relates to a magnetic resonance imaging apparatus and an imaging apparatus.
A magnetic resonance imaging (MRI) apparatus and other imaging apparatuses that visualize the inside of a subject or an object are utilized in various fields for medical and industrial purposes.
The magnetic resonance imaging apparatus that is one of the imaging apparatuses irradiates electromagnetic waves to a subject lying down in a static magnetic field space, and scans the subject so as to excite the subject's spins through nuclear magnetic resonance (NMR). Images expressing subject's slices, that is, subject's sections are produced based on magnetic resonance (MR) signals induced by the spins excited due to the scanning.
In the magnetic resonance imaging apparatus, a dynamic scanning technique of sequentially performing a plurality of scans with a time interval between adjoining scans is implemented (refer to, for example, Patent Document 1).
Japanese Unexamined Patent Publication No. 2002-165775
In the dynamic scanning, for example, a subject is asked to enter a non-breathing state at intervals, and timings of performing respective scans are designated in advance so that each scan will be performed in the non-breathing state. In the dynamic scanning, scans are performed in the non-breathing state according to the timings designated in advance. Consequently, the dynamic scanning is widely adopted because deterioration in image quality derived from respiratory body motion can be prevented.
However, when the dynamic scanning is implemented, if a subject cannot enter or retain the non-breathing state, the timings of performing respective scans designated in advance may be inconsistent with the timings when the subject enters the non-breathing state. In this case, low-quality images are produced. Scans may have to be performed again. This may lead to degradations in imaging efficiency and maneuverability alike.
In particular, when the dynamic scanning is implemented with a contrast medium injected into a subject, since there is often difficulty in re-injecting the contrast medium into the subject, the drawback that the imaging efficiency and maneuverability degrade may become obvious.